We report on the effect of ZnCdS/ZnS and ZnCdSe/ZnS core/shell quantum dots (QDs) on the efficiency of organic photovoltaic (OPV) cells. The QDs were deposited on the back side of indium tin oxide/glass substrates by spin coating with poly (methyl methacrylate). The short circuit current (J(SC)) and power conversion efficiency (PCE) of the OPV cells with ZnCdS/ZnS QDs + poly(methylmethacrylate) (PMMA) (8.07 mA/cm(2) and 3.2%) are higher than those of the control device without QDs (7.68 mA/cm(2) and 3.0%) because the wavelength of the injected light is changed to the absorption wavelength of the active layer of the OPV cells. However, the J(SC) and PCE of the OPV cells with ZnCdSe/ZnS QDs + PMMA are lower than those of the control device (6.62 mA/cm(2) and 2.44%) due to the low transmittance of the QDs + PMMA and discordance between the emission peak of the QDs and absorption peak of the active area in the OPV cells. (C) 2013 Elsevier B.V. All rights reserved.